Switch device with improved interlock structure



1968 J. A. RANKIN 3,396,247

SWITCH DEVICE WITH IMPROVED INTERLOCK STRUCTURE 2 Sheets-Sheet 1 Filed June 10, 1966 C [Ill 8 se 66 3 .37 60 60 Z 52 5 I a i 66 68 if 68 3g 1 39 25 p) i 79 i I I I I I z! I 79 ,7? @36 3 P5 ,0 .=5 1% i Q :1 i'll I 2 1 T: :3

l 1 F 1 LA F III III III IIIIIII/I/I/I/I IIIIIIIII III III I BM, ,5M 3M J. A. RANKIN Aug. 6, 1968 SWITCH DEVICE WITH IMPROVED INTERLOCK STRUCTURE 2 Sheets-Sheet Filed June 10, 1966 United States Patent 3,396,247 SWITCH DEVICE WITH IMPROVED INTERLOCK STRUCTURE John A. Rankin, St. Joseph, Mich, assignor to V-M Corporation, Benton Harbor, Mich., a corporation of Michigan Filed June 10, 1966, Ser. No. 556,640 19 Claims. (Cl. 200) ABSTRACT OF THE DISCLOSURE A switch device having an actuating rod axially depressible in a principal direction to actuate a control switch, a spring to resist downward movement of the actuating rod, a push button associated with the actuating rod to effect selective depression thereof, and interlock means operatively associated with either the push button or actuating rod to prevent downward depression of the rod with first either rotating the push button or moving it in a direction transverse to the principal direction.

This invention relates to switch devices and more particularly to .a switch device employing a novel safety interlock to prevent accidental actuation of the switch.

This invention finds particular utility where a number of closely spaced push button switches are used and it is desirable that at least one of the switches be provided with a safety lock to prevent accidental depressing or actuation thereof.

For example, in the field of recording-reproducing devices, and in particular, the field of magnetic recording-reproducing wherein information is recorded on a tape, it is a general practice to provide a series of push button type switches on the device which are associated respectively with the play, record, advance forward, rewind, and stop functions. When an operator desires to perform one of these functions, it is merely necessary to depress or actuate the proper push button. Prior art recorder-reproducing devices have generally utilized individual switches for the functions of record and play. Conventionally, an erasing function is associated with the record push button and is simultaneously actuated with the recording function such that any information previously recorded on the tape is erased immediately ahead of the recording of new information on the tape. Obviously, no such erasing function is combined with energizing of the playing head. Moreover, it will be appreciated that if the record push button switch is depressed accidentally while intending to depress another function switch, the information previously recorded on the tape will be erased with consequent undesirable results.

It is therefore a principal object of the present invention to provide a push button switch depressible in a principal direction which switch includes an interlock means which must be initially disengaged by a simple movement of the push button in a direction other than the principal direction before the depressing motion to actuate a control function. r

A more specific object of the present invention is to provide a novel interlock in that one of several push button switches of, for example, a magnetic tape recording reproducing machine, which actuates the recording and therefore also the erasing function to prevent unintentional depressing of the recording push button on the wrong assumption that the button controlling the play function is being depressed.

Another object of the present invention is to provide a novel and improved interlock on a record push button switch which includes a minimum number of parts and provides for ease and economy of manufacture.

ice

In one preferred embodiment of the invention a plurality of push buttons which include stem portions are supported on a frame structure for reciprocal axial movement and are depressible to actuate individual control functions. The push button stem which controls the record function includes a peripherally located notch which is positioned to engage a stop supported on the frame structure when the record push button is in its raised position to thereby prevent direct axial downward movement of the notched stem. Coil springs are provided to bias the push buttons to their raised positions while a second biasing means is provided to urge the notch into engagement with the stop member when the record push button is in its raised position. Consequently, in order to depress the record button, it is necessary to first move the record push button laterally to release the stop member from the stern notch. Because the other push buttons are operated in a conventional manner and do not require that the buttons be first slid laterally before depressing them axially, the aforesaid modification of the record actuating button acts as a safeguard against its unintentional depression when the operator had actually intended to depress another actuating button. Obviously, if the play head control button is pressed when the record head control button is intended, no immediate undesirable consequences will occur as the operator is alerted to his wrong selection by the sound from the amplifier.

Other objects and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a top plan view illustrating a recorderreproducer device having a plurality of push button switches associated therewith for selecting the function desired to be per-formed;

FIGURE 2 is an elevation sectional view taken along the line 2-2 of FIGURE 1 illustrating a preferred embodiment of the invention showing push button switches supported on a frame structure and having actuating lever members and circuit contact points associated therewith;

FIGURE 3 is a transverse sectional view taken substantially along line 3-3- of FIGURE 2 illustrating the enlarged or elongated aperture in the carrier plate which receives the record push button stem member;

FIGURE 4 is a transverse view taken along the line 4-4 of FIGURE 2 illustrating the stop member in cooperation with the notch in the record push button stem;

FIGURE 5 shows a partial elevation sectional view similar to FIGURE 2 and illustrates a further embodiment of the subject invention;

FIGURE 6 shows a fragmentary elevation view, partly in section, similar to FIGURE 2 illustrating another embodiment of the subject invention;

FIGURE 7 is a top view of the embodiment illustrated in FIGURE 6;

FIGURE 8 is a fragmentary elevation view, partly in section, similar to FIGURE 5 illustrating a further embodiment of the subject invention;

FIGURE 9 is a fragmentary elevation view taken substantially at right angle to FIGURE 8 along the line 99; and

FIGURE 10 is a transverse sectional view taken substantially along line 10-10 of FIGURE 8.

Referring now to FIGURE 1, there is illustrated a recorder-reproducer device represented generally by the numeral 10 and incorporating features of the present invention. The recorder-reproducer 10 includes a housing member 12 adapted to have a tape-feed reel 14 and a tapetake up reel 16 mounted thereon which provide supply and take-up means for a tape 18. The tape 18 is guided to a transducer housing 20 which contains a first transducer head a to perform the function of erase, and a second transducer head 20]) to perform the function of record or playback in a conventional manner. Mounted on the forward portion of the housing 12 are a number of push button switches indicated at 22, 24, 26, 28 and 30 which serve as actuating means and are depressible to perform, respectively, the functions of rewinding, stop, fast forward, play, and record. The record push button 30, when depressed, serves to close a switch contact 31 (FIGURE 2) which closes a circuit to the transducer heads 20a and 20b to perform the function of erasing and recording as the tape 18 passes the respective heads. That is, when the record push button 30 is depressed, means operative to erase information previously recorded on tape 18 operate simultaneously with means to record new information thereon. Play button 28, when depressed, serves to close a switch contact 33 which in FIGURE 2 is shown in closed position to complete a circuit to the transducer head 20!) to effect playing of information recorded on the tape as the tape passes thereby.

Play button 28 is of conventional construction in that it employs a stem or actuating rod portion 35 reciprocally mounted so as to allow it to be depressed against resistance of a coil spring 37 and to close switch 33. The stem 35 is provided with a pin 39 which is adapted to ride upon a cam surface 68 of the latch bar 71 and to be received within a notch 74 in the latch bar 71 so as to hold or retain stem 35 in a downward or depressed position and thereby switch 33 in closed relation. The pin 39 will be released from the notch 74 to thereby open switch 33 and allow upward movement of stem 35 upon depressing record push button 30 as will be described hereinbelow.

The frame structure which supports the push button switches may be of conventional construction suitable to adequately support the respective push button stem portions for reciprocal axial movement. One form of the support frame structure in accordance with the present invention comprises a generally horizontal carrier plate 32 which may be made integral with, or otherwise secured to, the housing member 12 of the recorder-reproducer. Side support frame members 34, 36 and 41 depend from the carrier plate 32 at substantially right angles thereto and are secured to the carrier plate in any suitable man ner, such as by soldering, welding or bolting. The carrier plate 32 is provided with apertures such as 38 and 38 which receive stem portions and 35, respectively, of the push buttons 28 and 30 shown in FIGURE 2. It will be understood that the aperture 38 must be made oversize relative to the stem 40 of record push button 39 to allow lateral movement of the push button 30 relative to carrier plate 32. A preferred configuration of aperture 38 provides an elongated slot (FIGURE 3) which serves to allow lateral movement of the stem 40 in a preferred direction.

The stem 40 of push button 30 serves as an actuating rod for lever members associated therewith, as will be explained hereinbelow. The stem 40 has an upper portion 42 and a lower portion 44. The upper portion 42 of the stem 40 passes through the elongated aperture 38 in the carrier plate 32, in a direction generally normal to the plane of the carrier plate and has a notch 46 provided in the peripheral surface thereof. The notch may be positioned axially along the upper stem 42 at a point convenient to manufacturing and space requirements as will be evident hereinafter. The notch 46 may have any configuration necessary to receive a stop member 48, but includes at least a fiat transverse surface 50 at the upper end thereof. Preferably, the notch 46 has an inclined portion 51 at its lower end.

The stop member 48 may be mounted on the support frame below the carrier plate 32 in any suitable manner so as to be aligned with the notch 46 and underlie surface 50 thereof when the record push button 30 is in its raised position. In FIGURE 4, the stop member 48 is shown as comprising a generally rectangular member when viewed in a plane transverse to the longitudinal axis of stem portion 42 and includes a depending flange portion 49 riveted to depending side support frame 36 so as to provide a relatively inflexible cantilevered stop member. As previously noted, the free end of stop member 48 is positioned at a distance below carrier plate 32 such that when the push button member 30 is in its raised position, as shown in FIGURE 2, the free end of stop 48 engages in notch 46 under the cooperating tension of a blade spring 52 and prevents direct axial downward movement of the stem 40 and push button 30 due to the stop member underlying surface 50.

The lower portion 44 of stem 40 is connected to the upper portion 42 through the generally flat blade spring 52 having its end secured respectively to upper stem portion 42 and lower portion 44 in a conventional manner, such as by small rivets 54 and 56, or by soldering thereto. The blade spring 52 serves to bias the upper portion 42 of stem 40 to a position such that the longitudinal axes of stem portions 42 and 44 are coincident, thus acting to urge notch 46 into engagement with stop member 48 when the push button 30 is in its upward position. The blade spring 52 is of such a configuration and stiffness that it will accommodate a force directed longitudinally thereof and ensure axial movement of the lower portion 44 of stem 40 upon axial movement of the upper portion 42.

A pair of generally parallel support partitions 58 and 60 are secured to the side support frame members 34, 36 and 41 in any conventional manner such as by soldering or bolting thereto and have central apertures 62, 63, and 64, 65, respectively, therein which receive the stern portions 35 and 44 of push buttons 28 and 30, respectively, therethrough in sliding relation. The partitions 58 and 60 serve to guide the push button stems as they are axially reciprocated to their raised and lowered positions.

As in the case of push button 28, a coil spring 82 which serves to bias push button 30 upwardly is disposed in coaxial relation with the lower stem portion 44 and is in terposed between a spring seat plate 84 on the stern portion 44 and the lower support partition member 60. The spring seats 84 are limited in upward movement on stems 35 and 40 by pins 85. The pin 85 is secured on the stem 44 at an axial position such that when the pin 85 abuts the lower surface 88 of support partition 58, the notch 46 in the upper stem portion 42 is aligned to engage the stop member 48.

The lower end of the lower portion 44 of stem 40 has a pin member 66 rigidly secured thereto in similar fashion to pin 39 on stem 35, described above. The pin 66 is positioned to engage the cam surface 68 on upstanding portion 70 of latch bar 71 when the push button 30 is depressed. The latch or locking bar 71 is mounted for horizontal movement and is biased to the left as viewed in FIGURE 2 by a coil spring 73 interposed between the side support frame 34 and a spring seat 75 secured to the bar 71. It will be seen that when the record push button 30 is depressed or moved downwardly from it raised position, as shown in FIGURE 2, the pin 66 will engage cam surface 68 and cause locking bar 71 to be moved to the right. As the latch or locking bar 71 is moved to its furthest righthand position, as determined by pin 66, the pin 39 on stem 35 of push button 28 will be released from its respective locking notch 74 in the locking bar 71. Further pressing of record button 30 will cause pin 66 to be received by its respective locking notch 74 at which time coil spring 73 effects movements of locking bar 71 to the left to thereby lock push button 30 in a downward position, push button 28 having been simultaneously moved to a raised position by spring 37. Conversely, depression or downward movement of push button 28 would effect the release of pin 66 from locking slot 74 through engagement of pin 39 with cam surface 68 in a manner similar to that just described.

A second set of pins 76 and 77 are provided on stems 44 and 35, respectively, and serve to engage actuating lever 72 when the respective push buttons 28 and 30 are moved to their downward depressed positions. The actuating lever 72 is associated with a pressure roller 78 (FIGURE 1) through linkage means (not shown) to elfect engagement of the pressure roller with a drive capstan 80 when either push button 28 or 30' is depressed to its downward position thereby moving actuating lever 72 from its upwardly biased position 72'. The actuating lever 72 and the associated linkage means for effecting engagement of the pressure roller and drive capstan form no part of the present invention and are included merely for illustrative purposes in combination with the switch assembly.

FIGURE 5 illustrates a further embodiment of the subject invention wherein a push button switch 90 is supported by a structure similar to that shown in FIGURE 2. Identical numerals in FIGURES 2 and 5 indicate identical parts. In the embodiment disclosed in FIGURE 5, push button stem member 92 is of one piece construction having a notch 46 therein which has a configuration similar to the notch shown in FIGURE 2. A stop member 48 is also provided which engages the notch 46 and prevents downward axial movement of stem 92 when push button 90 is in its raised position. Preferably, a coil spring 96 is interposed between the side support frame member 36 and stem 92 and has its end portions secured respectively to the frame member and the stem as at 98 and 100. The spring 96 is tensioned to resist lateral movement of stem 92 in elongated slot 38 of carrier plate 32 and thereby serves to bias the stern notch 46 into engagement with stop member 48 when push button 90 is in its raised position. It will be understood that stem 92 must have adequate column strength to resist bending under a longitudinal load when push button 90 is depressed.

In each of the described embodiments, When the push button switch 30, or 90 in FIGURE 5, is in its raised inoperative position, as illustrated in FIGURE 2, the stop member 48 engages notch 46 to prevent downward axial movement of the respective push buttons. Consequently, record head control switch 31 cannot be closed by simply depressing button 30, as can be done with play head control switch 33 by depressing push button 28. Rather, in order to move the push button 30 and its associated stem portion 42 axially downward to effect operation or actuation of the associated latch bar 71 and actuating lever 72 adjacent the lower end of stem portion 44, it is necessary to first move the push button 30 and stem portion 42 laterally in the elongated aperture 38 in carrier plate 32 to disengage the notch 46 of stem 40 from the stop member 48 allowing the push button 30 to be axially depressed.

FIGURES 6 and 7 illustrate another embodiment of the subject invention showing a pair of pivotally mounted push buttons which are representative of a plurality of such buttons as may be used in a control device, one of the push buttons being associated with a safety stop to prevent accidental depression thereof. Referring to FIGURE 6, a pair of push buttons 110 and 112 are pivotally mounted upon a support rod 114. The support rod 114 is supported on the carrier plate 32 in any suitable manner, such as by bent flaps 116, 116' and 116" which may be formed from the carrier plate and bent backwardly over the support rod 114. The push buttons 110 and 112 receive the rod 114 therethrough in sliding relation and are positioned to overlie the upper ends of a pair of actuating rods 118 and 120, respectively, such that upon selected downward depression of the push buttons the actuating rods will be moved axially downward. It will be understood that carrier plate 32 must be provided with appropriate openings therein through which push buttons 110 and 112 may operatively project. The actuating rods 118 and 120 have their bottom end portions adapted to engage a locking bar and switch device which comprise a control means as was previously described and illustrated in FIGURE 2. Coil springs 37 and 82 act between support partition 60 and spring seat plates 84 to bias the actuating rods 118 and to their upward position wherein the pin members 85, which are secured to rods 118 and 120 to limit upward travel of plates 84, abut the bottom surface of partition member 58. The coil springs 37 and 84 serve the same purpose as did the corresponding springs of the same reference numerals in FIGURE 2.

The bent flaps 116 and 116' of carrier plate 32 which support rod 114 immediately adjacent either side of push button 112 are spaced so as to allow push button 112 to freely pivot about rod 114 while preventing any substantial movement of the push button longitudinally on the rod. The flaps 116 and 116" on either side of push button 110 are spaced apart a greater distance than the width of push button 110 to allow movement of the push button longitudinally on the support rod 114. The position of the flaps 116 and 116" on either side of push button 110 is such that the push button overlies the upper end of actuating rod 118 at all times when the push button is moved longitudinally on the support rod 114.

A stop member 112 is secured to the underside of carrier plate 32 in a position to underlie the push button 110 when the push button is in its righthand position when viewing FIGURES 6 and 7. The stop member 122 may be secured to carrier plate 32 in any conventional manner, such as by a rivet 124. The stop member 122 has a width sufficient to underlie push button 110 when the push button is in its righthand position, but is short enough to allow the push button to disengage the stop member when the push button is moved to its lefthand position on the support rod 114 as shown in dash lines in FIGURES 6 and 7.

A coil compression spring 126 is coaxially disposed on the support rod 114 between flap 116' and the push button 110 so as to bias the push button to a position overlying stop member 122. Preferably, 'but not necessarily, the compression spring 126 may be wound to act as a torsion spring and connected to flap 1'16 and push button 110' to thereby bias the push button 110 to an upward pivotal position. If the spring 126 is used as a torsion spring, a stop member 128 will be provided adjacent the rear edge of push button 110 to limit the upward pivotal movement of the push button due to the biasing of the torsion spring. The stop member 128 may comprise an upstanding leg formed integral with or otherwise suitably secured to the carrier plate 32.

When it is desired to depress the push button 110 to effect a control function through the lower portion of actuating rod 118, it is first necessary to move the push button 110 to the left, when viewing FIGURE 6, against the force of spring 126 to remove it from the stop memher 122. Conversely, when a downward depressing force is removed from the push button 110 after having depressed the actuating rod 118, the compression spring 82 will cause the actuating rod 118 to be raised to its upward position. When actuating rod 118 reaches its uppermost position, the lower surface 127 of push button 110 will be slightly above the stop member 122 so that the spring member 126 will cause the button 110 to be moved to its righthand position overlying the stop member 122. Thus, it will be seen that the stop member 122 serves to prevent downward movement of the push but-- ton 110 until such time as the push button is moved to the left to disengage the stop member 122.

Referring now to FIGURES 8, 9 and 10, a further embodiment of the present invent-ion is illustrated wherein a push button indicated generally :at 130, is shown having a safety means associated therewith to prevent accidental depression. The push button 130 is rotatably supported on an actuating rod 132 which has a control switch at the lower end thereof (not shown) to effect a control function similar to that on the lower end of actuating rod 35 in FIGURE 2. A coil spring 37 is interposed between the partition member 60 and a spring seat member 84 to bias rod 132 to an upward position in similar fashion to the embodiment illustrated in FIGURE 2.

The push button 130 has an upper portion 134 and a lower portion 136, the upper portion 134 having a larger diameter than the lower portion 136 and being received within an aperture 138 provided in the carrier plate 32. The upper portion 134 of the push button has a vertical depth sufficient to allow depression of actuating rod 132 and push button 130 to effect a control function without the upper portion 134 being depressed below the carrier plate 32.

The lower portion 136 of push button 130 has an axial recess 140 therein which receives the upper end of actuating rod 132 in sliding relation such that the push button 130 may be freely rotated upon the actuating rod 132. The push button 130 is retained on actuating rod 130 in fixed axial relation through a pin 142 and slot 144 arrangement. The pin 142 is fixedly secured to the actuating rod 132 and projects radially therefrom through slot 144 provided in the lower portion 136 of the push button in sliding relation. The circumferential length of slot 144 is sufficient to allow angular rotation of push button 130 on shaft 132 as will become apparent herein'below.

A torsion spring 146 is coaxially disposed on the actuating rod 132 and serves to bias push button 130 in counterclockwise rotation (FIGURE The torsion spring has its lower end fixedly secured to a radially projecting pin 148 on rod 132 while the opposite upper end is fixed to the bottom surface 150 of push button 130 in any suitable manner such as through a vertically extending end portion 152 (FIGURE 8) of the spring being snugly received within a bore in the bottom of the push button.

The lower portion 136 of push button 130 has a radially extending projection or offset portion 156 formed integral therewith or otherwise secured thereto which extends axially downward from the upper portion 134 of the push button. The radial projection or offset portion 156 has a lower end surface 158 which is adapted to engage a stop member, shown generally at 160, in overlying relation when the push button is in its upward position. The stop member 160 has a vertical leg portion 162 and a horizontal leg portion 164 (FIGURE 9) which form a generally L-shaped bracket to receive the offset extension 156 of the push button. The stop member 160 is secured to a support frame member 166 which in turn is suitably secured to the bottom of the carrier plate 32.

When the push button 130 is in its upward position, the torsion spring 146 will bias it in a counter clockwise direction about the actuating rod 132 such that the offset projection 156 will overlie the horizontal portion 164 of stop member 160 and prevent depression of the push button. The push button will be rotated until the vertical surface 157 of the projection 156 engages vertical leg portion 162 of the stop member to thereby limit the rotational movement of the push button. When it is desired to depress push button 130 to effect a control function, the push button must first be rotated in a direction to release the offset portion 156 of the push button from the stop member 160'. When the depressing force is released from push button 130, or when a latch bar such as latch bar 71 of FIGURE 2 is disassociated from the shaft 132, the compression spring 37, having been previously compressed, will return the actuating rod 132 to its upward position wherein the lower surface 158 of offset portion 156 is slightly raised from the upper surface of horizontal portion 164 of stop member 160. Torsion spring 146 will then rotate the push button to a position such that offset portion 156 overlies stop member 1 60 to thereby prevent further depression of the push button without first rotating it to free the offset portion 156 from the stop member.

While the present invention has been described in connection with a magnetic recorder-reproducing device, it

will be obvious to those skilled in the art that the invention will have utility in other push button operated devices where it is advantageous to provide a safety lock to prevent accidental or unintentional depressing of one of the push buttons. Moreover, it will be understood that various changes, modifications, and uses may 'be made of the present invention without departing from its broader aspects and I therefore intend to cover all such changes and modifications which fall within the true spirit and scope of my invention in the following claims.

I claim:

1. A control switch device comprising an actuating means which is movable in a principal direction to actuate a control switch, resilient means resisting movement of said actuating means in said principal direction, and means cooperating with said actuating means to selectively prevent movement thereof in said principal direction, said actuating means being movable in said principal direction to actuate the control switch only after a separate initiating rotary movement of said actuating means.

2. The device defined in claim 1 wherein said means cooperating with said actuating means to selectively prevent movement thereof includes a torsion spring adapted to resist rotational movement of said actuating means in a direction to allow movement of said actuating means in said principal direction.

3. A control switch device comprising actuating means including an actuating rod having a push button rotatably supported thereon, said actuating rod and push button being movable in a principal direction to actuate a control switch, resilient means resisting movement of said actuating rod and push button in said principal direction, stop means cooperating with said push button to selectively prevent movement thereof in said principal direction, said push button including means associated with said stop means to prevent movement thereof in said prin cipal direction without an initial rotational movement of said push button.

4. The device defined in claim 3 wherein said means cooperating with said actuating means to selectively prevent movement thereof in said principal direction includes an offset portion on said push button, a stop member adapted to underlie said offset portion when said push button is in an upward non-operative position, and spring means adapted to bias said push button to a position wherein said offset portion overlies said stop member when said push button is in an upward non-operative position.

5. The device defined in claim 3 including means to retain said push button in fixed axial relation on said actuating rod while allowing said push button to be rotated relative to said actuating rod.

6. A control switch device comprising an actuating rod reciprocally mounted for axial movement in a principal direction to actuate a control switch, a push button pivotally mounted for movement into engagement with said actuating rod to axially depress said actuating rod, resilient means resisting movement of said actuating rod in said principal direction, and means cooperating with said push button to selectively prevent movement thereof to depress said actuating rod, said means for selectively preventing movement of said push button being adapted to allow said push button to engage said actuating rod only after an initiating movement of said push button in a direction transverse to said principal direction.

7. The device defined in claim 6 including a support rod adapted to support said push button for pivotal and longitudinal sliding movement thereon, said means for selectively preventing movement of said actuating rod comprising a stop member adapted to underlie said push button when in a first position on said support rod to thereby prevent downward pivotal movement of said push button, said push button being slidable on said support rod to disengage said stop member whereby said push button may be pivotally depressed downwardly to move said actuating rod in said principal direction.

8. The device defined in claim 7 wherein said resilient means includes a spring means coaxially disposed on said support rod adjacent said push button, said spring means being adapted to bias said push button to said first position on said support rod.

9. The device defined in claim 8 including means to limit the upward pivotal movement of said push button about said support rod.

10. The device of claim 8 wherein said spring means further serves to bias said push button in an upward pivotal direction about said support rod.

11. A control switch device comprising a push button having a stem portion reciprocally mounted for axial movement in a principal direction to actuate a control switch, said stern including a peripherally located notch, resilient means resisting movement of said stem in said principal direction, a stop member supported to engage in said notch when said stem is in its raised position to selectively prevent movement of said stem in said principal direction, said stem having tensioning means associtaed therewith to retain said notch in engagement with said stop and being depressible to actuate said control switch only after first being moved laterally against the tension thereof to release said notch from said stop.

12. A control switch device comprising an actuating means which is movable in a principal direction to actuate a control switch, resilient means resisting movement of said actuating means in said principal direction, means cooperating with said actuating means to selectively prevent movement thereof in said principal direction, said actuating means being movable in said principal direction to actuate the control switch only after a separate initiating movement of said actuating means, and latch means for releasably holding said actuating means in a depressed position against the resistance of said resilient means.

13. A control device as defined in claim 11 wherein a coil spring is utilized to urge said stem against said stop to locate and retain said notch in engagement with said stop when said stem is in its raised position.

14. A control switch device as claimed in claim 11 wherein said stern comprises upper and lower portions connected by a blade spring, said upper portion including said peripherally located notch and being yieldingly urged against said stop by said blade spring such that said stop engages said notch when said stem is in its raised position, said blade further resisting deformation by a force acting axially on said stem to permit depressing of said stem against the resistance of said resilient means.

15. A control device comprising a plurality of actuating members, each actuating member being depressible in a principal direction to actuate a control switch, and resilient means resisting depression of said actuating members, one of said actuating members having a safety feature associated therewith to prevent unintentional depressing thereof, said safety feature comprising a stop member adapted to underlie a portion of said one of said actuating members when said actuating member is in its raised position, said one of said actuating members having tensioning means associated therewith to cause said actuating member to overlie said stop member when in its raised position and being depressible to actuate a control switch only after first moving said actuating member laterally against said tensioning means to release said actuating member from said position overlying said stop member.

16. A control switch device as defined in claim 15 wherein said actuating members each comprise a push button having a stem portion mounted for reciprocal axial movement thereof in said principal direction, one of said push buttons having a notch located on the periphery of the stem portion thereof, said notched stem having tensioning means associated therewith to retain said notch in engagement with said stop member and being depressible to actuate a control switch only after first moving said notched stern laterally against the tension thereof to release said peripheral notch from said stop.

17. A control switch device as defined in claim 16 wherein a coil spring is utilized to urge said notched stem towards said stop to locate and retain said stem with its notch captured by said stop when in its raised position.

18. A control switch device as defined in claim 16 wherein said notched stem comprises upper and lower portions connected by a blade spring, said upper portion having said notch provided on the periphery thereof and being yieldingly urged by said blade spring to a position wherein said notch is captured by said stop when aligned therewith as in the raised position of said notched stem, said blade spring further resisting deformation by a force acting axially on said notched stern thereby permitting depression of said notched stem against the resistance of said resilient means.

19. A control switch device as defined in claim 15 including latch means for selectively and releasably holding said actuating members in their depressed positions against the resistance of said resilient means, said latch means being adapted to release all of said actuating members other than that actuating member which is depressed.

References Cited UNITED STATES PATENTS 2,156,946 5/1939 Closson et al. 200-169 LARAMIE E. ASKIN, Primary Examiner.

J. R. SCOTT, Assistant Examiner. 

